Patch from David Brownell

This adds RTC support to the csb337 default config.  Both the AT91
and the ds1307 RTCs are enabled (rtc0 and rtc1 respectively).

The ds1307 is used to initialize the system time, since it's battery-backed.

From then on the AT91 RTC is used, since it's more capable (with both
alarm and update irqs, and system wakeup capability) even though it
needs manual initialization (symlink /dev/rtc to /dev/rtc0 for older
versions of hwclock, then "hwclock --systohc") in an rc script or
from inittab.
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>